Ortiz-Catalan and colleagues demonstrated a prosthetic arm connected with a titanium rod to the bone of a man whose arm was amputated between the elbow and shoulder. A surgical team led by Brånemark connected the prosthetic arm in January 2013 that offers mechanical stability and acts as an extension of the man’s amputated arm.

The device, made to look and feel like a real arm, has neuro-muscular electrodes woven under the skin to provide continuous sensory feedback that helps stimulate nerves and offer better control. In conventional socket prostheses, say the researchers, electrodes are placed on the skin rather than under it, and as a result can be disrupted by environmental factors such as changes in temperature and nearby electromagnetic interference (e.g., from heavy machinery), diminishing their reliability.

The electrodes connect to peripheral nerves and muscles, allowing the man to operate and control the device, over long periods during the day, as long as 18 hours at a time, with little physical fatigue. The device also provides sensory feedback in the hand that allows the man to fine-tune his gripping motion, to the point of handling fragile items. In addition, the sensors enable the man to sense touch in different parts of the hand to allow for complex hand movements, such as in tying shoelaces.

After tests in the lab, the patient took the prosthetic device on the road, literally. He works as a truck driver in northern Sweden, and according to the researchers, was able to function in the job, performing tasks such as clamping on trailer loads and operating machinery. He could also use the arm when unloading deliveries, including fragile items such as eggs.

“Reliable communication between the prosthesis and the body has been the missing link for the clinical implementation of neural control and sensory feedback,” says Ortiz-Catalan in Chalmers statement, “and this is now in place.” The team plans to further develop the device-to-brain signaling to make the prosthetic arm’s electronic connections more bi-directional. The researchers also expect to expand the number of patients testing the device.

The man demonstrates capabilities of the prosthetic arm in the following video.

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